Water-soluble substrate with resistance to dissolution prior to being immersed in water

ABSTRACT

A water-soluble substrate, and more particularly a water-soluble substrate that is resistant to dissolution, and methods of making the same are disclosed. The water-soluble substrate comprises a first surface and a second surface. A coating is applied to, and substantially covers at least one of said first and second surfaces. The elongation ratio between said coating and said water-soluble substrate is at least 1. Articles, such as pouches, made from the water-soluble substrate, are also disclosed herein.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Ser.No. 60/818,689, filed Jul. 5, 2006, the disclosure of which isincorporated by reference.

FIELD OF THE INVENTION

This invention relates to a water-soluble substrate, and moreparticularly a water-soluble substrate which has improved resistance todissolution prior to being immersed in water, and methods of making thesame. This invention also relates to articles, such as pouches, madefrom the water-soluble substrate.

BACKGROUND OF THE INVENTION

Water-soluble substrates are gaining wider acceptance for use aspackaging materials. Packaging materials include films, sheets, blown ormolded hollow bodies (i.e. sachets, pouches, and tablets), bottles,receptacles and the like. Often, water-soluble substrates, when used inthe preparation of certain types of these articles such as sachets andpouches, disintegrate and/or become sticky when exposed to small amountsof water or high humidity. This can make them unsuitable for usage inthe packaging and storage of the compositions contained therein.

The most common consumer complaint for water-soluble pouches is linkedto unwanted pouch dissolution when accidentally exposed to small amountsof water, such as when water gets inside the outer packaging in whichthe pouches are sold and stored after purchase, from wet hands, highhumidity, leaking sinks, or pipes during storage. This may cause thewater-soluble pouches to leak prior to use and/or stick together. Thesecond most frequent complaint is that of the water-soluble pouchfailing to fully dissolve upon use. Thus, there remains an unmet needfor water-soluble substrates and articles made therefrom, such assachets and pouches, which has improved resistance against exposure tosmall amounts of water yet can subsequently dissolve very quickly whenimmersed in an aqueous solution, such as rinse and/or wash water.Various methods are known in the art to retard the dissolution ofwater-soluble substrates, typically involving coating the water-solublesubstrate with a material which is water-insoluble. For example, U.S.Pat. No. 6,509,072 describes a water-soluble substrate comprising abarrier coating. The barrier coating is a polymeric film which forms acontinuous film on the water-soluble substrate. Another example of abarrier coating is described in WO 01/23460, assigned to KaoCorporation, wherein a surface of the water-soluble substrate is coatedwith a particulate or fibrous water-insoluble material

When these coated water-soluble substrates are processed for use aspackaging materials, they are typically being stretched. In certainareas, the substrate may be stretched even up to 200% or more. Thiscould cause the coating to break, and thus allow water to contact thesurface of the water-soluble substrate, leading to the above mentionedproblems.

It is therefore an aspect of the present invention to providewater-soluble substrates which have improved resistance to dissolutionprior to being immersed in water, even when these substrates have beenstretched and formed into articles such as pouches and sachets, yet cansubsequently dissolve very quickly when immersed in an aqueous solution,such as rinse and/or wash water.

SUMMARY OF THE INVENTION

The present invention relates to a water-soluble substrate comprising afirst surface and a second surface opposite to said first surface,having a coating applied to, and substantially covering at least one ofsaid first and second surfaces, characterized in that the elongationratio of said coating to said water-soluble substrate is at least 1.

The present invention also relates to an articles comprising thewater-soluble substrate, and to a method of making the water-solublesubstrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-section of a non-coated water-soluble substrate.

FIG. 2 shows a cross-section of one embodiment of a water-solublesubstrate according to the present invention.

FIG. 3 shows a cross-section of an article comprising a water-solublesubstrate according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to a water-soluble substrate, and moreparticularly a water-soluble substrate which has improved resistancedissolution prior to being immersed in water, and methods of making thesame. This invention also relates to articles comprising thewater-soluble substrate described herein.

Water-Soluble Substrate

FIG. 1 shows a cross-section of a water-soluble substrate 10. Thewater-soluble substrate 10 has a first surface 12, a second surface 14opposite to the first surface 12, and a thickness 16 between the firstsurface 12 and the second surface 14. The water-soluble substrate 10 canbe in the form of a film, a sheet, or a foam, and includes woven andnonwoven structures.

The water-soluble substrate is made of polymeric materials and has awater-solubility of at least 50 weight %, as measured by the method setout here after using a glass-filter with a maximum pore size of 20microns. Preferably, the water-solubility of the substrate is at least75 weight % or even more preferably at least 95 weight %.

50 grams±0.1 gram of substrate material is added in a pre-weighed 400 mlbeaker and 245 ml±1 ml of 25° C. distilled water is added. This isstirred vigorously on a magnetic stirrer set at 600 rpm, for 30 minutes.Then, the mixture is filtered through a folded qualitativesintered-glass filter with a pore size as defined above (max. 20micron). The water is dried off from the collected filtrate by anyconventional method, and the weight of the remaining material isdetermined (which is the dissolved fraction). Then, the % solubility canbe calculated.

Typically the water-soluble substrate 10 has a basis weight of from 0.33to 1,667 grams per square meter, preferably from 33 to 167 grams persquare meter. The thickness of the water-soluble substrate 10 betweenthe first surface 12 and the second surface 14 can range from about 0.75micrometer to about 1,250 micrometer, preferably from about 10micrometer to about 250 micrometer, more preferably from about 25micrometer to about 125 micrometer.

Preferred polymers, copolymers or derivatives thereof suitable for useas substrate material are selected from polyvinyl alcohol (PVA),polyvinyl pyrrolidone, polyalkylene oxides, acrylamide, acrylic acid,cellulose, cellulose ethers, cellulose esters, cellulose amides,polyvinyl acetates, polycarboxylic acids and salts, polyaminoacids orpeptides, polyamides, polyacrylamide, copolymers of maleic/acrylicacids, polysaccharides including starch and gelatine, natural gums suchas xanthum and carragum, polyacrylates and water-soluble acrylatecopolymers, methylcellulose, carboxymethylcellulose sodium, dextrin,ethylcellulose, hydroxyethyl cellulose, hydroxypropyl methylcellulose,maltodextrin, polymethacrylates, polyvinyl alcohol copolymers,hydroxypropyl methyl cellulose (HPMC), and mixtures thereof. The mostpreferred polymer is polyvinyl alcohol. Preferably, the level of polymerin the substrate is at least 60%.

An example of commercially available water-soluble films are PVA filmsknown under the trade reference Monosol M8630, as sold by Chris-CraftIndustrial Products of Gary, Ind., US, and PVA films of correspondingsolubility and deformability characteristics. Other films suitable foruse herein include films known under the trade reference PT film or theK-series of films supplied by Aicello, or VF-HP film supplied byKuraray.

Coating

As shown in FIG. 2, a coating 20 is applied to and substantially coversat least one of the first or second surfaces 12, 14 of the water-solublesubstrate 10. With “substantially covers”, it is meant that at least95%, preferably at least 99%, and most preferably 100% of the first orsecond surface 12, 14 is covered by the coating. This ensures that uponaccidental water-contact, the water will either not be able to reach thefirst or second surface 12, 14 of the water-soluble substrate 10, or theamount of water that reaches said surface, is not enough to completelysolubilise the water-soluble substrate 10.

The elongation ratio of the coating 20 to the water-soluble substrate 10is at least 1, preferably higher than 1, even more preferably from 1 to10, most preferably from 1.5 to 5. The elongation of a material isdefined as the percentage it can be stretched in one direction under aconstant force without breaking. Elongation can be measured according toASTM standard D 882-02. As such, an elongation ratio between the coating20 and the water-soluble substrate 10 of at least 1, means that thecoating 20 can be stretched as much as the water-soluble substrate 10,without breaking such that water can not reach the surface of thewater-soluble substrate 10.

The coating 20 preferably comprises a material which is lesswater-soluble than the water-soluble substrate, more preferablycomprises a material which is water-insoluble. With “water-insolublematerial”, it is meant that the solubility is less than 50 weight %, asmeasured according to the previously described method. Preferably thewater-solubility is less than 40 weight %, more preferably less than 30weight %, and most preferably less than 10 weight %.

Preferred coatings are coatings which can be elongated at least 20%,more preferably at least 30%, even more preferably at least 50%, evenmore preferably more than 100% and most preferably more than 200%,without breaking. Examples of such coatings are liquid polyurethanecoatings sold by Ideal Products LLC (Plymouth, Ind.) under the tradenameof Sani-Tred Permaflex™, or by HMG America LLC (Performance Coatings,Roebuck, S.C.) under the tradename Flexithane™. Other examples of suchcoatings are the acrylic-based dip coatings which are flexible at lowtemperatures, sold by JC Whitney Inc. (Chicago, Ill.). Highly preferredcoatings for use in the present invention are the coating coded SOP00090 supplied by ANI Printing Inks Group (Plymouth, Minn., USA), andthe latex based coating Krilon H2O brand supplied by Krilon ProductsGroup (Cleveland, Ohio, USA). Other examples are coatings comprisingflakes or particulates of a non-flexible or non-elastic material, mixedwith a lubricant or slip agent. This lubricant or slip agent ensuresthat, upon stretching of the water-soluble substrate, the flakes orparticulates can slide over one another. Preferred lubricants include,but are not limited thereto, talc, polytetrafluoroethylene (PTFE),cornstarch, silicone, wax, oil, polyolefins such as polyethylene,polypropylene, or combinations thereof.

The coating 20 can be applied in any suitable amount. Preferably, thecoating is applied in an amount of at least 0.1 parts, more preferablyat least 1 part, even more preferably at least 10 parts, per 100 partsby weight of the water-soluble substrate. Preferably, the amount ofcoating applied to said water-soluble substrate 10 ranges from at least0.1 to 200, more preferably from 1 to 150, even more preferably from 1to 100, even more preferably from 10 to 80 parts, per 100 parts byweight of the water-soluble substrate 10.

The coatings according to the present invention are preferably coloredcoatings in order to create visually appealing effects, such asgraphics, cartoons, logo's, branding, user's instructions, and the like.

Optional Ingredients

It may be required for certain applications that the dissolution rate(when immersed) of the substrate is increased. Disintegrants may beadded to the coating in order to speed up the dissolution when thewater-soluble substrate is immersed in water. Preferably, the level ofdisintegrant in the coating is from 0.1 to 30%, preferably from 1 to15%, by weight of said coating. Alternatively, disintegrants may also beapplied on the surface of the water-soluble substrate 10, opposite tothe surface onto which the coating is applied, or they may be appliedonto both surfaces of the water-soluble substrate 10, or they may beintegrated into the water-soluble film 10, or any combination thereof.Suitable disintegrants for use herein are corn/potato starch, methylcellulose/celluloses, mineral clay powders, croscarmelose (cross-linkedcellulose), crospovidine (cross-linked polymer), sodium starch glycolate(cross-linked starch).

The water-soluble substrate-forming composition and the water-solublesubstrate 10 formed therefrom can also comprise one or more additive oradjunct ingredients. For example, the water-soluble substrate-formingcomposition and the water-soluble substrate 10 may contain:plasticizers, lubricants, release agents, fillers, extenders,anti-blocking agents, de-tackifying agents, antifoams, or otherfunctional ingredients. The latter may, in the case of articlescontaining compositions for washing, include, but are not limited tofunctional detergent additives to be delivered to the wash water, forexample organic polymeric dispersants, or other detergent additives.

The water-soluble substrate 10, as noted above, may comprise aplasticizer. Suitable plasticizers include, but are not limited to:glycerol, glycerin, diglycerin, hydroxypropyl glycerine, sorbitol,ethylene glycol, diethylene glycol, triethylene glycol, tetraethyleneglycol, propylene glycol, polyethylene glycols, neopentyl glycol,trimethylolpropane, polyether polyols, ethanolamines, and mixturesthereof. The plasticizer can be incorporated in the water-solublesubstrate 10 in any suitable amount including amounts in the range offrom about 5% to about 30% by weight, preferably in the range of fromabout 12% to about 20% by weight.

Suitable surfactants may include the nonionic, cationic, anionic andzwitterionic classes. Suitable surfactants include, but are not limitedto, polyoxyethylenated polyoxypropylene glycols, alcohol ethoxylates,alkylphenol ethoxylates, tertiary acetylenic glycols and alkanolamides(nonionics), polyoxyethylenated amines, quaternary ammonium salts andquaternized polyoxyethylenated amines (cationics), and amine oxides,N-alkylbetaines and sulfobetaines (zwitterionics). The surfactant can beincorporated in the water-soluble substrate 10 in any suitable amountincluding amounts in the range of from about 0.01% to about 1% byweight, preferably in the range of from about 0.1% to about 0.6% byweight.

Suitable lubricants/release agents include, but are not limited to,fatty acids and their salts, fatty alcohols, fatty esters, fatty amines,fatty amine acetates and fatty amides. The lubricant/release agent canbe incorporated in the water-soluble substrate 10 in any suitable amountincluding amounts within the range of from about 0.02% to about 1.5% byweight, preferably in the range of from about 0.04% to about 0.15% byweight.

Suitable fillers, extenders, antiblocking agents, detackifying agentsinclude, but are not limited to: starches, modified starches,crosslinked polyvinylpyrrolidone, crosslinked cellulose,microcrystalline cellulose, silica, metallic oxides, calcium carbonate,talc and mica. The filler, extender, antiblocking agent, detackifyingagent can be present in the water-soluble substrate 10 in any suitableamount including to amounts in the range of from about 0.1% to about 25%by weight, preferably in the range of from about 1% to about 15% byweight. In the absence of starch, it may be desirable for the filler,extender, antiblocking agent, detackifying agent to be present in arange of from about 1% to about 5% by weight.

Suitable antifoams include, but are not limited to, those based onpolydimethylsiloxanes and hydrocarbon blends. The antifoam can bepresent in the water-soluble substrate 10 in any suitable amountincluding amounts in the range of from about 0.001% to about 0.5%, or inthe range of from about 0.01% to about 0.1% by weight.

The composition is prepared by mixing the materials and agitating themixture while raising the temperature from about 70° F. (about 21° C.)to 195° F. (about 90° C.) until solution is complete. Thesubstrate-forming composition may be made into any suitable form (e.g.film or sheets) and may then be subsequently formed into any suitableproduct (e.g. single- and multiple-compartment pouches, sachets, bags,etc.).

Methods of Making a Water-Soluble Substrate

There are numerous non-limiting embodiments of the method of making thewater-soluble substrate 10 described herein.

In one embodiment, the method comprises providing a previously formedwater-soluble substrate 10 and applying a coating 20 to at least one ofthe surfaces 12, 14 of the previously formed water-soluble substrate 10.

The coating 20 can be applied to the previously formed water-solublesubstrate 10 in a number of different manners. In one non-limitingembodiment, the coating 20 is applied to at least one of the surfaces12, 14 of the previously formed water-soluble substrate 10 in the formof particles. One example of particles is rubber beads, which sticktogether after they have been applied to the surface of thewater-soluble substrate 10. Preferably, the particles are applied to thewater-soluble substrate 10 via a jet, or electro-statically. Due to thehigh speed of the jet, some of the particles are embedded into thesubstrate, thereby reducing, or even eliminating the need for using abinder. Also when the powder is applied electro-statically, a binder isgenerally not needed. Nevertheless, a binder may be used. The binder mayfirst be applied to the water-soluble substrate 10, before the particlesare applied. Or, alternatively, the binder may be mixed with theparticles, and then the mixture is added to the water-soluble substrate10.

In another non-limiting embodiment of the method, the coating 20 isprovided in the form of a solution that is applied onto at least one ofthe surfaces 12, 14 of the water-soluble substrate 10, and is allowed todry, or undergoes a drying process. The solution can be applied on thesubstrate by means of any coating process, including spray, knife, rod,kiss, slot, painting, printing and mixtures thereof. Printing ispreferred for use herein. Printing is a well established and economicprocess. Printing is usually done with inks and dyes and used to impartpatterns and colours to substrates but in the case of the inventionprinting is used to deposit the coating onto a water-soluble substrate.Any kind of printing method can be used, including rotogravure,lithography, flexography, porous and screen printing, inkjet printing,letterpress, tampography and combinations thereof. In a highly preferredembodiment, the coating is applied in several layers. A first coatinglayer is applied to the water-soluble substrate 10, and is then allowedto dry. Consequently, one or more additional coating layers may be addeduntil the desired coating thickness is obtained. As such, thinwater-soluble substrate can be used, yet made resistant to accidentalwater contact.

These embodiments may also comprise a step of wetting at least a portionof at least one of the surfaces 12, 14 of the water-soluble substrate 10prior to applying the coating 20 to the previously formed water-solublesubstrate 10. The wetting of at least one of the surfaces 12, 14 of thewater-soluble substrate 10 may be used to at least partially dissolve orsolubilize an outer portion of the surface 12, 14 of the substrate 10(that is, part of the way into the thickness of the substrate). Thewater-soluble substrate 10 may be at least partially solubilized to anysuitable depth in order to partially embed the coating into thesubstrate. Suitable depths include, but are not limited to: from about1% to about 40% or about 45%, from about 1% to about 30%, from about 1%to about 20%, from about 1% to about 15%, and alternatively, from about1% to about 10% of the overall substrate thickness 16. The coating 20 isthen applied to the partially dissolved portion of at least one of thesurfaces 12, 14 of the substrate 10. This allows the coating 20 to beembedded into an outer portion of the surface 12, 14 of the substrate10, and to become a more permanent part of the substrate 10. The wettedsurface 12, 14 of the substrate 10 with the coating 20 embedded into thesame is then permitted to dry. Such an embodiment of the method may alsocomprise a step of removing at least some of any loose or excess ofcoating 20 remaining on the surface of the water-soluble substrate 10after it has dried, such as by wiping or dusting the surface of thesubstrate 10.

In another embodiment, the coating 20 can be added to the water-solublesubstrate 10 after the substrate 10 is made into a product. For example,if the water-soluble substrate 10 is used to form a water-soluble pouchthat contains a composition, the coating 20 can be added to thesubstrate 10 on at least a portion of the surface of the water-solublepouch.

Methods of Making a Water-Soluble Pouch

The water-soluble substrate 10 described herein can be formed intoarticles, including but not limited to those in which the water-solublesubstrate 10 is used as a packaging material. Such articles include, butare not limited to water-soluble pouches, sachets, and other containers.

Water-soluble pouches and other such containers that incorporate thewater-soluble substrate 10 described herein can be made in any suitablemanner known in the art. The water-soluble substrate 10 can be providedwith improved resistance to solubility either before or after formingthe same into the final product. In either case, in certain embodimentsit is desirable when making such articles, that the surface 12, 14 ofthe substrate 10 on which the coating is applied, forms an outer surfaceof the product.

There are a number of processes for making water-soluble pouches. Theseinclude, but are not limited to processes known in the art as: verticalform-fill-sealing processes, horizontal form-fill sealing processes, andformation of the pouches in molds on the surface of a circular drum. Invertical form-fill-sealing processes, a vertical tube is formed byfolding a substrate. The bottom end of the tube is sealed to form anopen pouch. This pouch is partially filled allowing a head space. Thetop part of the open pouch is then subsequently sealed together to closethe pouch, and to form the next open pouch. The first pouch issubsequently cut and the process is repeated. The pouches formed in sucha way usually have pillow shape. Horizontal form-fill sealing processesuse a die having a series of molds therein. In horizontal form-fillsealing processes, a substrate is placed in the die and open pouches areformed in these molds, which can then be filled, covered with anotherlayer of substrate, and sealed. In the third process (formation ofpouches in molds on the surface of a circular drum), a substrate iscirculated over the drum and pockets are formed, which pass under afilling machine to fill the open pockets. The filling and sealing takesplace at the highest point (top) of the circle described by the drum,e.g. typically, filling is done just before the rotating drum starts thedownwards circular motion, and sealing just after the drum starts itsdownwards motion.

In any of the processes that involve a step of forming of open pouches,the substrate can initially be molded or formed into the shape of anopen pouch using thermoforming, vacuum-forming, or both. Thermoforminginvolves heating the molds and/or the substrate by applying heat in anyknown way such as contacting the molds with a heating element, or byblowing hot air or using heating lamps to heat the molds and/or thesubstrate. In the case of vacuum-forming, vacuum assistance is employedto help drive the substrate into the mold. In other embodiments, the twotechniques can be combined to form pouches, for example, the substratecan be formed into open pouches by vacuum-forming, and heat can beprovided to facilitate the process. The open pouches are then filledwith the composition to be contained therein.

The filled, open pouches are then closed, which can be done by anymethod. In some cases, such as in horizontal pouch-forming processes,the closing is done by continuously feeding a second material orsubstrate, such as a water-soluble substrate, over and onto the web ofopen pouches and then sealing the first substrate and second substratetogether. The second material or substrate can comprise thewater-soluble substrate 10 described herein. It may be desirable for thesurface of the second substrate onto which the coating is applied, to beoriented so that it forms an outer surface of the pouch.

In such a process, the first and second substrates are typically sealedin the area between the molds, and, thus, between the pouches that arebeing formed in adjacent molds. The sealing can be done by any method.Methods of sealing include heat sealing, solvent welding, and solvent orwet sealing. The sealed webs of pouches can then be cut by a cuttingdevice, which cuts the pouches in the web from one another, intoseparate pouches. Processes of forming water-soluble pouches are furtherdescribed in U.S. patent application Ser. No. 09/994,533, PublicationNo. US 2002/0169092 A1, published in the name of Catlin, et al.

Articles of Manufacture

As shown in FIG. 3, the present invention also includes articlescomprising a product composition 40 and a water-soluble substrate 10,which may be formed into a container 30, such as a pouch, a sachet, acapsule, a bag, etc. to hold the product composition. The surface of thewater-soluble substrate 10 which has the coating 20 applied thereto, maybe used to form an outside surface of the container 30. Thewater-soluble substrate 10 may form at least a portion of a container 30that provides a unit dose of the product composition 40.

For simplicity, the articles of interest herein will be described interms of water-soluble pouches, although it should be understood thatdiscussion herein also applies to other types of containers.

The pouches 30 formed by the foregoing methods, can be of any form andshape which is suitable to hold the composition 40 contained therein,until it is desired to release the composition 40 from the water-solublepouch 30, such as by immersion of the water-soluble pouch 30 in water.The pouches 30 can comprise one compartment, or two or more compartments(that is, the pouches can be multi-compartment pouches). In oneembodiment, the water-soluble pouch 30 may have two or more compartmentsthat are in a generally superposed relationship and the pouch 30comprises upper and lower generally opposing outer walls, skirt-likeside walls, forming the sides of the pouch 30, and one or more internalpartitioning walls, separating different compartments from one another.If the composition 40 contained in the pouches 30 comprises differentforms or components, the different components of the composition 40 maybe contained in different compartments of the water-soluble pouch 30 andmay be separated from one another by a barrier of water-solublematerial.

The pouches or other containers 30 may contain a unit dose of one ormore composition 40 for use as/in laundry detergent compositions,automatic dishwashing detergent compositions, hard surface cleaners,stain removers, fabric enhancers and/or fabric softeners, food andbeverage and new product forms where contact with small amounts of watercould create premature pouch dissolution, unwanted pouch leakage and/orundesirable pouch-to-pouch stickiness. The compositions 40 in thepouches 30 can be in any suitable form including, but not limited to:liquids, liquigels, gels, pastes, creams, solids, granules, powders,etc. The different compartments of multi-compartment pouches 30 may beused to separate incompatible ingredients. For example, it may bedesirable to separate bleaches and enzymes into separate compartments.Other forms of multi-compartment embodiments may include apowder-containing compartment in combination with a liquid-containingcompartment. Additional examples of multiple compartment water-solublepouches are disclosed in U.S. Pat. No. 6,670,314 B2, Smith, et al.

The water-soluble pouches 30 may be dropped into any suitable aqueoussolution (such as hot or cold water), whereupon water-soluble substrate10 forming the water-soluble pouches 30 dissolves to release thecontents of the pouches.

The water-soluble substrate 10 described herein can also be used forcoating products and other articles. Non-limiting examples of such aproduct are laundry detergent tablets or automatic dishwashing detergenttablets. Other examples include coating products in the food andbeverage category where contact with small amounts of water could createpremature dissolution, unwanted leakage and/or undesirable stickiness.

EXAMPLES

A flexible coating coded SOP 00090, supplied by ANI Printing Inks Group,is printed onto a standard PvOH M8630 soluble film supplied by Monosol.The following method is used to measure the water resistance of thecoated film vs. uncoated film.

To determine if a film is resistant to accidental water contact aproplet Test method is used. In this test, a pouch (approx. 2″×2″) isformed in a cavity and a droplet of 0.2 ml of room temperature water isadded to the formed side of the pouch. The formed side is the stressedcase for this test since the film is thinned during cavity formation. Astopwatch is started as soon as the water contacts the pouch and thetime when significant film deformation in the body of the pouch isobserved is recorded. This time, termed “Time to Deform” is a precursorto film failure.

Results

Material Time to Deform Uncoated M8630 film by Immediate (1 sec)Monosol, 3 mil thickness M8630 coated with No deformation SOP00090flexible coating

Latex based coating (Krilon H2O brand supplied by Krilon Products Group,Cleveland Ohio) is sprayed onto the standard PvOH M8630 soluble filmsupplied by Monosol.

Results

Material Time to Deform Uncoated M8630 film by Immediate (1 sec)Monosol, 3 mil thickness M8630 coated with Latex No deformation coating

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention. To the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. An article comprising a water-soluble substrate:a. made of polymeric materials selected from the group consisting ofpolyvinyl alcohol (PVA), polyvinyl pyrrolidone, polyalkylene oxides,acrylamide, acrylic acid, cellulose, cellulose ethers, cellulose esters,cellulose amides, polyvinyl acetates, polycarboxylic acids and salts,polyaminoacids, polyamides, polyacrylamide, copolymers of maleic/acrylicacids, polysaccharides, natural gums, polyacrylates and water-solubleacrylate copolymers, methylcellulose, carboxymethylcellulose sodium,dextrin, ethylcellulose, hydroxyethyl cellulose, hydroxypropylmethylcellulose, maltodextrin, polymethacrylates, polyvinyl alcoholcopolymers, hydroxypropyl methyl cellulose (HPMC), and mixtures thereof;and b. comprising a first surface and a second surface opposite to saidfirst surface, said first surface forming an outside surface of saidarticle and wherein at least a portion of said first surface is wettedand; and c. having a water-solubility of at least 50 weight %; wherein acoating having a solubility less than 50 weight % is applied as asolution to said first surface, such that said coating covers at least95% of said first surface; wherein the elongation ratio of said coatingto said water-soluble substrate is from about 1 to 10; and furtherwherein the water-soluble substrate has a thickness between the firstsurface and the second surface of from about 10 micrometers to about 250micrometers; and wherein the article is in the form of amulti-compartment water-soluble pouch that substantially dissolves inwater.
 2. A water-soluble substrate according to claim 1, wherein saidelongation ratio is from about 1.5 to about
 5. 3. A water-solublesubstrate according to claim 1, wherein said coating is applied to saidfirst and said second surfaces.
 4. An article according to claim 1,wherein the coating is applied in an amount of at least 0.1 parts byweight of the water-soluble substrate.
 5. An article according to claim1, wherein the water-soluble substrate is partially solubilized.
 6. Anarticle according to claim 1, wherein the water-soluble substrate issolubilized to a depth of from about 1% to about 45% of the overallwater-soluble substrate thickness.